Zuko listened as Katara cried to his uncle, sagging against the tree hiding him as he heard the reason she was upset.
He'd only hesitated a second when he'd blocked that door. The soldier had only been able to inform him that they were under attack, and he hadn't known if that had meant the Avatar had found them again or not. Whoever it was though, he knew he couldn't let them get to Katara. As he'd run to the deck, he'd been terrified he was going to lose her that night.
The warriors in black had been incredible fighters, further sparking the fear Zuko had so that his attacks had grown more and more dangerous as the warriors had pressed them back.
When Katara had appeared on that deck, Zuko had barely managed to keep from exploding in terror. Of course, she'd escaped. She was resourceful and smart, and she refused to be held back. Those were some of the reasons he'd come to start liking her, despite what he'd thought had been his better judgment.
But despite the moment of utter pride he'd experienced at seeing she'd escaped, fear had encompassed him, leading him to send such a devastating attack on the man Katara claimed was her father. Had Katara not had her waterbending, she would be dead right now.
He thought he had trusted her. He'd kissed her because he believed he trusted her. Somehow, she'd managed to push through his walls, learning more about him than anyone besides his uncle had been able to do, and he had believed he trusted her. That moment when he'd barricaded her inside the room without telling her anything proved he'd been wrong.
Listening to her crying, Zuko sunk into the sand, burying his head against his knees.
You tried so hard to keep from losing her, he thought to himself, that you'll end up being the reason she leaves.